That depends on your settings. By default, it is not required. It is only required if you set Registration Integration config option to Yes (mean users need to have an account to register for your event)
We have a mix of registered and public events. It would be nice to have a "User registration integration" override for each event so it can be turned off on certain events.
That's a strange requirement as none of customers requested for this feature before. Maybe in this case, you will have to customize the extension yourself to have this feature. It is not hard
